A number of diseases require segmental resection to remove part of an organ. For example, inflammatory diseases of the bowel (e.g. Crohn's disease, ulcerative colitis), colorectal cancer and bowel infarction may require removal of a section of the lower gastrointestinal (GI) tract. Following resection, the two ends of the GI tract must be reattached to one another to allow continued functioning. The process of this reattachment is known as surgical anastomosis.
A stoma is an artificial opening between two hollow organs or between one hollow organ and the outside of the body. The creation of artificial stomas such as colostomies, ileostomies, urostomies, oesophagostomies, and gastrostomies can be a useful medical intervention in disease treatment where the normal visceral tract must be bypassed to allow, for example, the discharge of waste or delivery of nutrition from/to the body.
Historically, anastomoses and stomas were achieved using conventional sutures. The conventional technique for stoma trephine construction involves stretching of the defect through the abdominal wall usually to accommodate the breadths of the surgeon's index and second fingers at the position of the second interphalangeal joints (Keighley, M. R. B. & Williams, N. S., “Surgery of the Anus Rectum and Colon”, 3rd Ed., Saunders Ltd., 2008). Such relatively uncontrolled stretching of the abdominal wall and particularly the rectus abdominis muscle is likely to result in weakness of the abdominal wall at the site of trephine creation with subsequent widening of the defect over time resulting in hernia formation. Surgical staplers have occasionally been described for stoma construction. Surgical staplers are more frequently used for anastomoses.
Conventionally, surgical circular staplers are used for anastomosis of hollow tubular organs, for example bowel, oesophagus and other tubular structures. Circular staplers can deliver two or more circumferentially mounted rows of staples to secure opposing sides of the tubular organ together. Simultaneously an internal circular cutting blade mounted in a stapler housing creates an internal lumen allowing normal functioning of lumen to be reconstituted following excision of diseased portions of the tubular organ. “Circular” refers to the substantially circular arrangement of staples that is delivered by the stapler.
Circular staplers in current use generally comprise an anvil and a stapler. The anvil docks onto the stapler via an anvil docking pin present on the stapler. However, the construction of current stapling devices restricts docking of the elements, namely the stapler anvil to the stapler, to within the body lumen. Certain new procedures or elements of current procedures would benefit, in terms of efficacy and safety, if this docking could be externalised.
Example circular staplers are described in WO 2004/089225, U.S. Pat. Nos. 4,576,167, 7,422,138, 7,318,830 and 7,547,312, the contents of which are incorporated herein by reference.
Contemporary colorectal surgery attempts to strike a balance between effecting disease cure and preservation of anatomy and function. Regrettably, this remains strikingly evident in the treatment of low rectal cancer when complete excision of the anorectum (APER) and the formation of permanent end colostomy are often still necessary to optimise oncological cure. Sphincter preservation in such patients is secondary to oncological cure and anorectum and normal anorectum functions sacrificed resulting in permanent colostomy with all the life affecting results, which have been well documented in the medical and public domains. Resolving this compromise has perhaps become the ‘holy grail’ of modern coloproctology.
Several techniques have been described to help secure an ultra-low anastomosis e.g. abdomino-trans-sacral, abdomino-transanal, abdomino-trans-sphincteric or intersphincteric. Each of these is technically extremely difficult to perform and may damage sphincteric mechanisms significantly with consequent severely impaired continence. As a result, these have not been widely adopted.
In addition to loss of sphincter function following low and ultra-low ileo or colo-rectal anastomosis, parastomal herniation is an extremely common complication following stoma formation, with a reported incidence of up to 48% over a 10-year period. Risk factors include obesity, malignancy, poor nutrition, steroid therapy and conditions which raise intra-abdominal pressure (Keighley and Williams, 2008). Loop stomas seem to be particularly prone to this complication, presumably because its construction requires a larger abdominal trephine compared with an end stoma. Such hernias cause considerable morbidity such as local pain and intestinal obstruction which may necessitate emergency surgery and bowel resection with a risk of mortality.
In the course of surgery to correct proctographic abnormalities in patients with disordered rectal evacuation, the inventors have used an anterior perineal approach to expose the plane between the rectum and vagina (or prostate) (Williams, N. S. et al., Br J Surg; 2005; 92:598-604). It became evident from such procedures that relatively easy access to the lower rectum and anal canal could be gained whilst allowing the external and internal anal sphincters to be retained intact. Indeed, the inventors have now demonstrated during open surgery the utility and safety of this approach, which is termed the APPEAR (Anterior Perineal PlanE for Anterior Resection) technique (Williams, N. S. et al., Ann Surg; 2008; 247:750-758), as an adjunct to performing conventional rectal excisional surgery in the context of low rectal carcinoma and large villous adenoma.
The resection and subsequent anastomosis of diseased pathology in the lower rectum, specifically the last 10 cms and in particular the last 5 cm of the rectum, is problematic using conventional stapling techniques where the position of the resection on the anal side is extremely low relative to the anal verge or there is insufficient space in the perineal cavity, created during the APPEAR procedure, to adequately bring the opposing anvil shaft and trocar (anvil docking pin) elements into approximation for docking.
There remains in the art a need for a surgical device and technique that allows construction of low and ultra-low ileo of colo-rectal anastomoses whilst maintaining sphincter integrity and thus continence. There also remains in the art a need for a surgical device and technique that allows the formation of stomas which avoid the problems such as parastomal hernias.